Bright and Fast‐Response Hybrid X‐Ray Scintillators by Molecular and Dielectric Confinement

Abstract Scintillators featuring bright and fast‐response properties are essential for high‐speed and dynamic X‐ray imaging. Nevertheless, simultaneously possessing high light yields and fast‐response remains a significant challenge for most scintillators. Herein, we propose a strategy to achieve the bright and fast‐response characteristics of scintillators by leveraging the combined effects of dielectric and molecular confinement in organic–inorganic hybrid scintillators (TPA) 2 MnBr 4 . Thereinto, large tetrapropylammonium cations (TPA + ) surround [MnBr 4 ] 2− units, forming a zero‐dimensional (0D) molecular confinement structure that promotes electron localization and achieves a notable light yield of 56800 photons MeV −1 . Meanwhile, the low dielectric constant of TPA + can enhance dielectric confinement of [MnBr 4 ] 2− units, mitigating exciton capture by deep defects. These synergistic effects in the scintillators lead to a large exciton binding energy of 1028.8 meV and an ultrafast response time of 500 fs. Notably, under the irradiation of X‐rays, (TPA) 2 MnBr 4 exhibits an extremely low detection limit of 18.7 nGy air s −1 and an exceptional spatial resolution of 21.0 lp mm −1 . Given the bright and fast‐response features of scintillators, we demonstrate the potential applications in 3D dynamic and real‐time X‐ray imaging. These findings lay the groundwork for designing high‐performance scintillators and open avenues for innovative applications in high‐resolution and dynamic imaging.